The feed to Sen. Bernie Sanders' (I., Vt.) interview on CNN was cut Friday night after he joked that the cable network is "fake news."
Fox News flagged the video over the weekend.
Host Erin Burnett asked Sanders to respond to a clip of President Donald Trump saying that he had not seen reports that National Security Adviser Michael Flynn discussed sanctions with Russian officials before the inauguration.
"I don't know about that, I haven't seen it," President Donald Trump said in the clip. "What report is that? I haven't seen that. I'll look at that."
"He says he knows nothing about it, hasn't seen any of these reports," Burnett said to Sanders. "Is that a problem?"
Sanders responded by saying that CNN is fake news. He did clarify that he was joking before the feed cut out.
"Well, I don't know, maybe he [Trump] was watching CNN fake news, what do you think?" Sanders asked.
Burnett laughed softly.
"You don't buy it?" she asked.
"That was a joke," Sanders said.
"I know it was a joke," Burnett said. "You don't buy what he said, obviously?"
"Erin?" Sanders asked.
Burnett spoke to him but Sanders could not hear her.
"Are we on?" he asked.
"It looks like we have lost connection with Sen. Sanders, so let's just try to get that back up," she said. "Do we have him back?"
She waited for five seconds before cutting to a commercial break to try to get him back.
Trump tweeted about the interview over the weekend, accusing CNN of intentionally ending the segment after Sanders' joke.
While on FAKE NEWS @CNN, Bernie Sanders was cut off for using the term fake news to describe the network. They said technical difficulties!
— Donald J. Trump (@realDonaldTrump) February 12, 2017
CNN responded to the president by calling his assertion false. The network provided a transcript of the interview as proof that the interview cut out because of technical issues.
@realDonaldTrump False. Transcript from @ErinBurnett intvu w @SenSanders. He was not cut off. Those are the facts. https://t.co/NzJNgdYSIX pic.twitter.com/AOFKLHUlGk
— CNN Communications (@CNNPR) February 12, 2017
Trump called CNN "fake news" during a press conference last month, accusing the network of pushing false information about him.